JPH0819895A - Full motor driven mechanical press - Google Patents

Abstract

PURPOSE:To obtain the press of simple construction, easy adjustment, easy maintenance, quiet operation and being compactly mounted to a cross head by not using a hydraulic system including a precisely constructed hydraulic cylinder and using an electrical motor and gear device. CONSTITUTION:The device is provided with a cross head 6 mounted to plural tie rods 4 connecting a bed 2 and upper frame 3 free to elevate, a ball screw mechanism 5 arranged between the cross head 6 and each tie rod 4 and a rotation drive device 20 to rotate a nut 5a of each ball screw mechanism 5 in forward/backward directions. The ball screw mechanism 5 is supported by a ball screw 5b formed in the tie rod 5b and the cross head 6 free to rotate and has the nut 5a meshed to each ball screw 5b, the rotation drive device 20 is placed on the upper face of cross head 6 and has an independent gear device 22, which transmits rotating drive power of an electric motor 21 respectively arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an all-electric mechanical press.

[0002]

2. Description of the Related Art A conventional press used for compression molding of, for example, a synthetic resin is an all-hydraulic press in which a hydraulic motor is driven by an electric motor and the pressure oil is sent to each hydraulic cylinder to drive a crosshead. Is. However, the present all-hydraulic press has the following technical problems.

(1) The hydraulic system and the hydraulic cylinder have a delicate structure and are expensive. (2) The occupied area of the hydraulic system (hydraulic unit) is large and a separate hydraulic chamber is required. (3) Adjusting the hydraulic system requires some specialized knowledge. Further, since energy is transmitted using oil as a medium, there is a change in mechanical performance due to a change in oil temperature, a degree of pollution, and the like. Therefore, it is important to manage the hydraulic oil and it takes time.

(4) There is a risk of fire and contamination due to oil leakage from hydraulic piping. (5) In the molding method that requires parallel control of the crosshead (movable frame), hydraulic pressure is servo-operated for parallel control, and a parallel control system and a cylinder, which are structurally complicated and expensive, are separately required. In addition, the accuracy of parallel control is limited, and the allowable eccentric pressing force and the allowable eccentric moment are also limited.

(6) A general full-hydraulic press requires the following types and numbers of hydraulic cylinders as actuators, and the maintenance of packing and the like is required periodically for each. Main cylinder (pressurizing cylinder) 1-3, lift cylinder (pullback cylinder) 2, release cylinder 4 (leveling cylinder (parallel control cylinder) 4) (7) There is noise generated from the hydraulic pump.

[0006]

The present invention has been made in view of the above conventional technical problems, and the structure thereof is as follows. According to the invention of claim 1, a press body 1 having a bed 2, an upper frame 3, and a plurality of tie rods 4 connecting the bed 2 and the upper frame 3, and a crosshead arranged on the tie rods 4 so as to be vertically movable. 6 and
A lower die 8 provided with a screw mechanism 5 provided between the crosshead 6 and each tie rod 4 and a rotation drive device 20 for rotationally driving the nut 5a of each screw mechanism 5 in the forward and reverse directions, and arranged on the bed 2. An all-electric mechanical press that performs press working with an upper die 7 arranged on the crosshead 6 facing the lower die 8, wherein the screw mechanism 5 includes a male screw 5b formed on each tie rod 4, and a crosshead 6 Is rotatably supported by
The rotation driving device 20 is installed on the upper surface of the crosshead 6 and has a nut 5a that meshes with each male screw 5b.
It is an all-electrical mechanical press having an independent gear device 22 for transmitting to a. In the configuration of the invention of claim 2, each electric motor 21 is composed of a servo motor, and each gear device 2 is formed by each servo motor.
2. The all-electric mechanical press according to claim 1, wherein the parallel accuracy of the crosshead 6 is controlled via 2. According to the third aspect of the invention, the independent gear device 22 is provided.
Between the gears 22, a single synchronous gear 35 that meshes with a predetermined gear 28b symmetrically arranged in each gear device 22 and is rotatably supported by the crosshead 6 is provided. 35. The all-electric mechanical press according to claim 1, characterized in that it is mechanically secured by 35.

[0007]

According to the first aspect of the invention, the nut 5a of each screw mechanism 5 is rotationally driven in the forward and reverse directions by the rotary drive device 20 installed on the upper surface of the crosshead 6 to raise and lower the crosshead 6. That is, the individually arranged electric motors 21 are rotationally driven in one direction, and the rotational driving force is transmitted to the nuts 5a of the screw mechanisms 5 via the independent gear devices 22. Since each nut 5a is rotatably supported by the crosshead 6 and meshes with the male screw 5b formed on the tie rod 4, the crosshead 6 can be lowered by rotating the nuts 5a in one direction. By sufficiently lowering the crosshead 6, the lower die 8 placed on the bed 2 and the upper die 7 placed on the crosshead 6 facing the lower die 8 can be pressed. In addition,
According to the present invention, even if the press load point between the upper and lower dies 7 and 8 is eccentric, the position of the upper and lower dies 7 and 8 can be continuously corrected by controlling the rotation speed of each electric motor 21. It is possible to maintain the desired parallelism of

The individually arranged electric motors 21 are rotationally driven in the other directions, and the rotational driving force is transmitted to the nuts 5a of the screw mechanisms 5 via the independent gear devices 22 to raise the crosshead 6. be able to. By raising the crosshead 6 sufficiently, the upper and lower molds 7,
8 can be opened.

According to the invention of claim 2, each electric motor 2
Since 1 is composed of a servo motor, it is possible to precisely control the number of revolutions of each electric motor 21 and maintain the parallel accuracy of the crosshead 6, and thus the parallelism between the upper and lower molds 7 and 8 at a high level. it can.

According to the third aspect of the invention, a single synchronous gear 35, which is meshed with a predetermined gear of each gear device 22 and is rotatably supported by the crosshead 6, is provided between the independent gear devices 22. Electric motors 2 arranged separately because they are provided
The rotational driving force of 1 is transmitted to each nut 5a by the action of the synchronous gear 35 in a mechanically and forcibly synchronized state. As a result, the parallel accuracy of the crosshead 6 can be maintained at a high level. The synchronous gear 35
The number of s may be substantially single.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of an all-electric mechanical press. In the drawings, reference numeral 1 indicates a press body, and the press body 1 includes a bed 2 at a lower end portion, an upper frame 3 at an upper end portion, and a plurality of beds (4 in this example) that connect the bed 2 and the upper frame 3 to each other. Tie rod 4 of.
A cross head 6 (movable frame) is supported on the tie rod 4 via a ball screw mechanism 5 so as to be movable up and down, and is opposed to an upper die 7 fixed to the lower surface of the cross head 6 so as to face the upper surface of the bed 2. The lower die 8 is disposed in the.

As shown in FIG. 1, the ball screw screw mechanism 5 includes a nut 5a (female screw), which is a cylindrical ball screw rotatably supported by the crosshead 6 such that relative movement in the vertical direction is impossible, and each tie rod. 4 and a ball screw 5b (male screw) which is a worm, and nuts 5a are screwed to the ball screws 5b of each tie rod 4 with balls (not shown) interposed. The ball screw mechanism 5 has a normal structure, and the friction of the contact surface of the screw is reduced by the rolling of the ball. Each nut 5a has a nut 5a and a spur gear 28a which will be described later as one body, and both upper and lower ends thereof are supported by a cross head 6 by a thrust self-aligning roller bearing such that the nut 5a is rotatable and cannot move up and down relatively. .

The nuts 5a are individually driven to rotate by the rotary drive device 20. Each rotary drive device 20 is installed on the upper surface of the crosshead 6, and has an electric motor 21, a gear device 22, and a brake device 23.
Each electric motor 21 is configured by a servo motor, and as shown in FIG. 3, is arranged symmetrically in the front, rear, left, and right with the gear device 22 on the upper surface of the crosshead 6. Here, the servo motor is a motor that automatically detects and corrects the amount of deviation when it deviates from a specified number of revolutions, and is a servo motor using an induction motor, a brushless motor, or the like.

As shown in FIG. 3, the gear unit 22 is a chain or the like wound between the motor shaft of the electric motor 21 and one end of a first rotary shaft 24 which is rotatably supported horizontally on the crosshead 6. Wrapping device 25 and, as shown in FIG.
A bevel gear device 27 interposed between the other end of the first rotary shaft 24 and one end of a second rotary shaft 26 rotatably vertically supported by the crosshead 6, and the other end of the second rotary shaft 26. And a spur gear device 28 interposed between the above portion and the upper end portion of the nut 5a. One spur gear 28a of the spur gear device 28 is fixed to the nut 5a.

Further, the brake device 23 includes the first rotary shaft 2
4, a spur gear device 30 is interposed between a third rotating shaft 29 rotatably and horizontally supported on the crosshead 6, and the braking force of the brake device 23 is applied to the third rotating shaft 29 such as a brake disc. It is designed to act on.

By rotating each electric motor 21 in the forward and reverse directions, the nut 5 is moved through the gear device 22.
a is rotationally driven in the reverse direction. That is, each electric motor 2
If 1 is rotationally driven in the forward and reverse directions, the wrapping device 25 and the first
The rotary driving force is transmitted by the rotary shaft 24, the bevel gear device 27, the second rotary shaft 26, and the spur gear device 28, and the spur gear 28
The nut 5a integral with a is rotationally driven in the forward and reverse directions. Also,
By operating each brake device 23, a braking force acts on the third rotary shaft 29, the spur gear device 30, the first rotary shaft 24, the bevel gear device 27, the second rotary shaft 26, and the spur gear device 28. The rotation of the nut 5a, which is rotationally driven by each electric motor 21, is braked.

Further, a position detector 9 for detecting the vertical position of the crosshead 6 is provided. The position detection device 9
Bed 2 and cross head 6 corresponding to each tie rod 4.
It can be configured by a potentiometer, an encoder, or the like provided between and. Each of the position detecting devices 9 detects the position of the crosshead 6 in the vertical direction, performs arithmetic processing on the detected value by a computer (not shown), and then rotates each electric motor 21 according to a command from the servomotor amplifier. To control. This functions as a parallel control mechanism that adjusts the vertical position of each corner of the crosshead 6. The origin of the pair of upper and lower molds 7 and 8 is set by the computer in the mold origin matching mode, and four independent electric motors 2 are used.
The cross head 6 is provided by the rotary drive device 20 composed of one or the like.
While lowering and pressing the upper and lower molds 7 and 8 to reset the read numerical values of the position detecting devices 9 at the four positions, respectively. The origin at 8 is determined.

Next, the operation of the first embodiment will be described. First, when the upper and lower molds 7 and 8 are attached to the press body 1, the computer is caused to adopt the mold origin alignment mode, and the rotary drive device 20 including the four electric motors 21 and the like.
To lower the crosshead 6 to move the upper and lower molds 7, 8
Is set so that the detection value of each position detecting device 9 becomes zero.

From this state, press working such as compression molding is performed on the synthetic resin. If the workpiece is put on the lower die 8 and each electric motor 21 is driven to rotate in one direction, the winding tool 2
5, first rotating shaft 24, bevel gear device 27, second rotating shaft 26
Also, the nuts 5a integrated with the spur gear 28a are rotationally driven in one direction via the spur gear 28. Thus, along with the ball screw 5b of each tie rod 4, each nut 5a gradually descends along with the crosshead 6. in this way,
A ball screw screw mechanism 5 is interposed between each tie rod 4 and the cross head 6, and the ball screw screw mechanism 5
Is a nut 5a rotatably supported by the crosshead 6.
And a ball screw 5b formed on each tie rod 4. Therefore, each tie rod 4 need only be non-rotatably fixed to the bed 2, and can be firmly fixed to the bed 2 with a simple structure. Also, the nut 5a
Need only be supported so that the crosshead 6 can rotate and can be moved up and down integrally with the crosshead 6, and the support can be facilitated by a simple structure.

When the crosshead 6 and the upper die 7 are gradually lowered in this manner, the parallelism of the crosshead 6 is monitored by the position detecting devices 9 as needed. When a deviation occurs in the parallelism between the upper and lower molds 7 and 8 which are aligned with the mold origin, parallelism maintenance control is performed based on the detection value of each position detection device 9. That is, the position detecting device 9 appropriately raises the rotation speed of the electric motor 21 corresponding to the position indicating that the crosshead 6 takes the upper position, and prompts the lowering of the corresponding position, while the crosshead 6 moves to the lower position. The number of rotations of the electric motor 21 corresponding to the location indicating that to take is reduced and the relevant location is relatively increased. At that time, the brake device 23 corresponding to a position indicating that the crosshead 6 takes the lower position is operated, and the third rotating shaft 29 and the spur gear device 3 are operated.
0, first rotary shaft 24, bevel gear device 27, second rotary shaft 26
By applying a braking force to the spur gear device 28 and braking the rotation of the predetermined nut 5a, the biased and lowered state of the crosshead 6 is promptly corrected.

By using a servo motor as the electric motor 21, the deviation of the parallelism between the upper and lower molds 7 and 8 when the crosshead 6 descends is small, and the parallelism maintenance control is performed. Is also made finely. The weight of each rotary drive device 20 installed on the upper surface of the crosshead 6 is
It acts as a pressing force between the lower molds 7 and 8.

FIGS. 4 to 6 show a second embodiment of the all-electric mechanical press, parts substantially the same as those of the first embodiment are designated by the same reference numerals, and their description will be omitted. In the second embodiment, as shown in FIG. 4, a spur gear 33 is meshed with the other gear 28b of the spur gear device 28 of the second rotary shaft 26, and the spur gear 33 is the fourth rotation with the clutch 13 interposed. Axis 3
6 is connected to the spur gear 34. Spur gear device 28
The gears 28b are symmetrically arranged as described above, and the spur gears 33 and 34 are also symmetrically arranged on the upper surface of the crosshead 6. Furthermore, it meshes with all (4) spur gears 1
The synchronous gear 35, which consists of individual spur gears, is attached to the crosshead 6
It is rotatably supported at the center of the. Each clutch 13
Has a function of connecting and disconnecting between the synchronous gear 35 and each gear device 22, and in a disconnected state, each nut 5a can be individually rotationally driven by each electric motor 21.

Next, the operation of the second embodiment will be described. First, when the upper and lower molds 7 and 8 are attached to the press main body 1, the computer is made to adopt a mold origin alignment mode, and each clutch 13 is disengaged, and it is composed of four electric motors 21 and the like. The cross drive 6 is lowered by the rotation drive device 20 and the detection values of the respective position detection devices 9 are set to zero while the upper and lower molds 7 and 8 are pressurized. In a state where the function of the synchronous gear 35 is temporarily lost by disconnecting each clutch 13, the read numerical values of the four-point position detecting device 9 are reset respectively, so that specific upper and lower molds 7, 8
The origin at is determined. After the completion of the origin alignment, each clutch 13 is connected.

From this state, press working such as compression molding is performed. If a workpiece is put on the lower die 8 and each electric motor 21 is driven to rotate in one direction, the winding tool 25 and the first rotating shaft 2
4, bevel gear device 27, second rotating shaft 26 and spur gear device 2
The nut 5a is rotationally driven in one direction via 8, and the nut 5a is gradually lowered along with the ball screw 5b of each tie rod 4 together with the crosshead 6. At that time, the spur gears 33, 34 and the second rotary shaft 2 are operated by the action of the synchronous gear 35.
Since the spur gear device 28 of 6 rotates in exact synchronization, as long as the origins of the upper and lower molds 7 and 8 are accurately aligned, the crosshead 6 and the upper mold 7 are mechanical and forced. It descends with the parallelism maintained. Like this, 4
The pair of rotary drive devices 20 are driven accurately in synchronization by the action of the synchronous gear 35, and the parallelism between the upper and lower molds 7 and 8 is forcibly ensured. It is also possible to use something other than a motor. Further, it is of course possible to use another screw mechanism instead of the ball screw screw mechanism 5.

[0025]

As can be understood from the above description,
According to the all-electric mechanical press of the present invention, the following effects can be obtained. (1) Since an electric motor and a gear device are used without using a hydraulic system including a hydraulic cylinder with a fine structure,
It has a simple structure, is relatively quiet, and can be compactly mounted on a crosshead. In addition, the risk of fire and the risk of contamination due to oil leakage from the hydraulic piping are eliminated. (2) The hydraulic system is not used, the adjustment is relatively easy, and the mechanical performance does not change due to the temperature change of oil and the degree of pollution. As a result, the structure is simple and the wear is difficult, and the maintenance is easy. Further, since the crosshead is lowered by the plurality of electric motors, the parallelism between the upper and lower molds can be controlled.

According to the second and third aspects of the present invention, the parallel control of the crosshead is performed by a simple structure, and the parallel state between the upper and lower molds during the mold clamping process is maintained well. Therefore, it is possible to obtain a molded product of good quality having a predetermined wall thickness with a relatively simple structure. As a result, it is suitable for molding synthetic resin materials.

[Brief description of drawings]

FIG. 1 is a front view showing an all-electric mechanical press according to a first embodiment of the present invention, with a part of which is cut out and a part of which is omitted.

FIG. 2 is a side view of the same.

FIG. 3 is a plan view of the same without the upper frame.

FIG. 4 is a front view showing an all-electric mechanical press according to a second embodiment of the present invention with a part of which is cut out and a part of which is omitted.

FIG. 5 is a side view of the same.

FIG. 6 is a plan view without the upper frame.

[Explanation of symbols]

1: Press body, 2: Bed, 3: Upper frame, 4: Tie rod, 5: Ball screw screw mechanism (screw mechanism),
5a: Nut, 5b: Ball screw (male screw), 6: Crosshead, 7: Upper mold, 8: Lower mold, 20: Rotation drive device,
21: electric motor, 22: gear device, 28b: gear,
35: Synchronous gear.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takeshi Suzuki, No. 4 Chatsu-cho, Muroran-shi, Hokkaido Company of Nikko Tokki Co., Ltd. (72) Inventor Mitsunori Date No. 4 Chatsu-cho, Muroran-shi, Hokkaido, Nikko Co., Ltd.

Claims (3)

[Claims] 1. A press body (1) having a bed (2), an upper frame (3) and a plurality of tie rods (4) connecting the bed (2) and the upper frame (3), and a tie rod (4). Crosshead (6) that can be moved up and down freely
And a screw drive (5) provided between the crosshead (6) and each tie rod (4) and a rotation drive device (20) for rotationally driving the nut (5a) of each screw mechanism (5) in the forward and reverse directions. And an all-electrical mechanical press machine including a lower mold (8) arranged on the bed (2) and an upper mold (7) arranged on the crosshead (6) facing the lower mold (8). In the press, the screw mechanism (5) includes the tie rods (4).
And a nut (5a) that is rotatably supported by the crosshead (6) and that meshes with each male screw (5b). The rotary drive device (20) includes a crosshead (5b). 6) An all-electric mechanical press having an independent gear device (22) installed on the upper surface of 6) and transmitting the rotational driving force of the individually arranged electric motors (21) to each nut (5a). 2. Each electric motor (21) is composed of a servo motor, and the parallel accuracy of the crosshead (6) is controlled by each servo motor via each gear device (22). The all-electric mechanical press according to claim 1. 3. A predetermined gear (28) symmetrically arranged between the gear devices (22) between the independent gear devices (22).
b) has a single synchronous gear (35) that is rotatably supported by the crosshead (6), and the parallel accuracy of the crosshead (6) is mechanically adjusted by the synchronous gear (35). The all-electric mechanical press according to claim 1, which is secured.